Scheduling in license assisted access

ABSTRACT

According to some embodiments, a method in a network node comprises determining a first uplink/downlink scheduling pattern for a first plurality of consecutive subframes; transmitting the first uplink/downlink scheduling pattern to a wireless device; transmitting at least one subframe to the wireless device according to the first uplink/downlink scheduling pattern; determining a second uplink/downlink scheduling pattern for a second plurality of consecutive subframes, wherein the first plurality of consecutive subframes and the second plurality of consecutive subframes share at least one subframe; and transmitting the second uplink/downlink scheduling pattern to the wireless device.

PRIORITY

This application is a continuation, under 35 U.S.C. § 120 of U.S.Utility patent application Ser. No. 15/159,305 filed on May 19, 2016which claims priority to U.S. Provisional Patent Application No.62/165,025 flied May 21, 2015 both of which are hereby incorporated byreference in their entirety.

RELATED APPLICATION

This application claims benefit under 35 U.S.C. § 119(e) to U.S.Provisional Application Ser. No. 62/165,025, entitled “METHODS OF LAASCHEDULING BROADCAST,” filed May 21, 2015, the entire content of whichis incorporated herein by reference.

TECHNICAL FIELD

Particular embodiments relate generally to wireless communicationsnetworks, and more particularly to subframe scheduling for licenseassisted access (LAA).

BACKGROUND

The Third Generation Partnership Project (3GPP) initiative referred toas License Assisted Access (LAA) enables long term evolution (LTE)equipment to operate in the unlicensed 5 GHz radio spectrum. Theunlicensed 5 GHz spectrum is used as a complement to the licensedspectrum. Accordingly, devices connect in the licensed spectrum (primarycell or PCell) and use carrier aggregation to benefit from additionaltransmission capacity in the unlicensed spectrum (secondary cell orSCell). To reduce the changes required for aggregating licensed andunlicensed spectrum, the LTE frame timing in the primary cell issimultaneously used in the secondary cell.

Regulatory requirements, however, may not permit transmissions in theunlicensed spectrum without prior channel sensing. This is because theunlicensed spectrum is shared with radios of similar or dissimilarwireless technologies. Wireless devices may perform channel sensingusing a listen-before-talk (LBT) method. Today, the unlicensed 5 GHzspectrum is mainly used by equipment implementing the IEEE 802.11Wireless Local Area Network (WLAN) standard. This standard is knownunder its marketing brand “Wi-Fi.”

In Europe the LBT procedure is under the scope of EN 301.893 regulation.For LAA to operate in the 5 GHz spectrum, the LAA LBT procedure conformsto requirements and minimum behaviors set forth in EN 301.893.Additional system designs and steps, however, are needed to ensurecoexistence of Wi-Fi and LAA with EN 301.893 LBT procedures. Forexample, U.S. Pat. No. 8,774,209 titled “Apparatus and method forspectrum sharing using listen-before-talk with quiet periods” describesframe-based orthogonal frequency division multiplexing (OFDM) systemsthat use LBT to determine whether a channel is free prior totransmission. A maximum transmission duration timer is used to limit theduration of a transmission burst, and is followed by a quiet period.

LTE uses OFDM in the downlink and DFT-spread OFDM (also referred to assingle-carrier FDMA) in the uplink. The basic LTE downlink physicalresource comprises a time-frequency grid as illustrated in FIG. 1.

FIG. 1 illustrates an example OFDM symbol. The horizontal axisrepresents time and the other axis represents frequency. Each resourceelement corresponds to one OFDM subcarrier during one OFDM symbolinterval. An uplink subframe has the same subcarrier spacing as thedownlink and the same number of SC-FDMA symbols in the time domain asOFDM symbols in the downlink. In the time domain, LTE downlinktransmissions are organized into radio frames.

FIG. 2 illustrates an example radio frame. Each radio frame is 10 ms andconsists of ten equally-sized subframes of length Tsubframe=1 ms. Fornormal cyclic prefix, one subframe consists of 14 OFDM symbols. Theduration of each symbol is approximately 71.4 μs.

Resource allocation in LTE is typically described in terms of resourceblocks, where a resource block corresponds to one slot (0.5 ms) in thetime domain and 12 contiguous subcarriers in the frequency domain. Apair of two adjacent resource blocks in time direction (1.0 ms) is knownas a resource block pair. Resource blocks are numbered in the frequencydomain, starting with 0 from one end of the system bandwidth.

Downlink transmissions are dynamically scheduled. In each subframe abase station transmits control information about which terminals data istransmitted to and upon which resource blocks the data is transmitted inthe current downlink subframe. This control signaling is typicallytransmitted in the first 1, 2, 3 or 4 OFDM symbols in each subframe andthe number n=1, 2, 3 or 4 is known as the Control Format Indicator(CFI). The downlink subframe also contains common reference symbols,which are known to the receiver and used for coherent demodulation ofe.g. the control information.

FIG. 3 illustrates an example downlink subframe. The subframe includesreference symbols and control signaling. In the illustrated example, thecontrol region includes 3 OFDM symbols (i.e., CFI=3). The referencesymbols include cell specific reference symbols (CRS) which may supportmultiple functions including fine time and frequency synchronization andchannel estimation for certain transmission modes.

For LTE Rel-8 to Rel-10, a base station schedules downlink transmissionsusing a Physical Downlink Control Channel (PDCCH). From LTE Rel-11 andonwards, downlink transmissions may also be scheduled on an EnhancedPhysical Downlink Control Channel (EPDCCH).

The PDCCH/EPDCCH carries downlink control information (DCI) such asscheduling decisions and power-control commands. For example, the DCIincludes downlink scheduling assignments such as Physical DownlinkShared Channel (PDSCH) resource indication, transport format, hybrid-ARQinformation, and control information related to spatial multiplexing (ifapplicable). A downlink scheduling assignment also includes a commandfor power control of the Physical Uplink Control Channel (PUCCH) usedfor transmission of hybrid-ARQ acknowledgements in response to downlinkscheduling assignments. The DCI may also include uplink schedulinggrants such as Physical Uplink Shared Channel (PUSCH) resourceindication, transport format, and hybrid-ARQ-related information. Anuplink scheduling grant also includes a command for power control of thePUSCH. The DCI may also include power control commands for a set ofterminals as a complement to the commands included in the schedulingassignments/grants.

One PDCCH/EPDCCH carries one DCI message containing one of the groups ofinformation listed above. Because a base station may schedule multipleterminals simultaneously, and each terminal may be scheduled on bothdownlink and uplink simultaneously, multiple scheduling messages may betransmitted within each subframe. Each scheduling message is transmittedon separate PDCCH/EPDCCH resources. Consequently, multiple simultaneousPDCCH/EPDCCH transmissions are typically within each subframe in eachcell. Furthermore, support for different radio-channel conditions mayuse link adaptation. In link adaptation the code rate of thePDCCH/EPDCCH is selected by adapting the resource usage for thePDCCH/EPDCCH to match the radio-channel conditions.

In LTE, the eNB transmits the uplink transmission scheduling command tothe user equipment (UE). The LTE standard specifies a fixed delaybetween the time the scheduling command is transmitted and the time theUE transmits the uplink signal. This delay provides the UE time todecode the PDCCH/EPDCCH and prepare the uplink signal for transmission.For a frequency division duplex (FDD) serving cell, the uplink, grantdelay is 4 ms. For a time division duplex (TDD) serving cell, the uplinkgrant delay can be greater than 4 ms.

The LTE Rel-10 standard supports bandwidths larger than 20 MHz. Onerequirement of LTE Rel-10 is backward compatibility with LTE Rel-8. Thisincludes spectrum compatibility. One way to provide compatibility is foran LTE Rel-10 carrier wider than 20 MHz to appear as a number of LTEcarriers to an LTE Rel-8 terminal. Each such carrier may be referred toas a Component Carrier (CC).

For early LTE Rel-10 deployments, the number of LTE Rel-10-capableterminals will likely be smaller than the number of LTE legacy terminalsalready in existence. Thus, efficient use of a wide carrier is neededfor legacy terminals, i.e. providing carriers where legacy terminals maybe scheduled in all parts of the wideband LTE Rel-10 carrier. Onesolution uses carrier aggregation. Using carrier aggregation, an LTERel-10 terminal may receive multiple component carriers. The componentscarriers may have the same structure as a Rel-8 carrier.

FIG. 4 illustrates an example of carrier aggregation. A system bandwidthof 100 MHz may be represented by 5 component carriers each with 20 MHzbandwidth. A UE capable of carrier aggregation may be assigned a primarycell (PCell), which is always activated, and one or more secondary cells(SCells) which may be activated or deactivated dynamically.

The number of aggregated component carriers as well as the bandwidth ofthe individual component carriers may be different for uplink anddownlink. A symmetric configuration refers to a configuration where thenumber of component carriers in downlink is the same as in uplink. Anasymmetric configuration refers to a configuration where the number ofcomponent carriers is different between downlink and uplink. The numberof component carriers configured in a cell may be different from thenumber of component carriers seen by a terminal. For example, a terminalmay support more downlink component carriers than uplink componentcarriers, even though the cell is configured with the same number ofuplink and downlink component carriers.

Another feature of carrier aggregation is the ability to performcross-carrier scheduling. Cross-carrier scheduling enables a (E)PDCCH onone component carrier to schedule data transmissions on anothercomponent carrier using a 3-bit Carrier Indicator Field (CIF) insertedat the beginning of the (E)PDCCH messages. For data transmissions on agiven component carrier, a UE expects to receive scheduling messages onthe (E)PDCCH of just one component carrier (i.e., either the samecomponent carrier, or at different component carrier via cross-carrierscheduling). The mapping from (E)PDCCH to PDSCH may be configuredsemi-statically.

In LTE, the scheduling information for uplink and downlink transmissionson the PCell is transmitted on the PCell using (E)PDCCH. LTE refers tothis scheduling mechanism as a self-scheduling method. For a SCell, LTEsupports two scheduling mechanisms—self-scheduling or cross-scheduling.Using SCell self-scheduling (similar to PCell self-scheduling), theuplink and downlink scheduling information for the SCell is transmittedon the same SCell using (E)PDCCH. In SCell cross-scheduling, the networkconfigures a SCell via higher layer signaling to use a cross-schedulingmechanism. In this approach, the uplink and downlink schedulinginformation for a SCell is transmitted on a second cell using (E)PDCCH.The second cell may be the PCell or another SCell. In LTE, the downlinkand uplink scheduling mechanisms are configured together (i.e., thedownlink and uplink transmissions of a cell are either bothself-scheduling or both cross-scheduling).

Another wireless network technology that may share unlicensed spectrumwith LTE is a wireless local area network (WLAN). Typical WLANdeployments use carrier sense multiple access with collision avoidance(CSMA/CA) for medium access. This means that the channel is sensed toperform a clear channel assessment (CCA), and a transmission isinitiated only if the channel is determined to be idle. If the channelis determined to be busy, then the transmission is deferred until thechannel is idle. When the range of several access points using the samefrequency overlap, all transmissions related to one access point mightbe deferred when a transmission on the same frequency to or from anotheraccess point which is within range is detected. Effectively, if severalaccess points are within range of each other, they will need to sharethe channel in time, and the throughput for the individual access pointsmay be severely degraded.

FIG. 5 illustrates an example WLAN listen-before-talk mechanism. After afirst Wi-Fi station transmits a data frame to a second Wi-Fi station,the second station transmits an ACK frame back to the first station witha delay of 16 μs. The ACK frame is transmitted by the second stationwithout performing a LBT operation. To prevent another stationinterfering with the ACK frame transmission, a station defers for aduration of 34 μs (referred to as DIFS) after the channel is observed tobe occupied before assessing again whether the channel is occupied.

Thus, a station that wishes to transmit first performs a clear channelassessment by sensing the medium for a fixed duration DIFS. If themedium is idle, then the station assumes that it may take ownership ofthe medium and begins a frame exchange sequence. If the medium is busy,the station waits for the medium to go idle, defers for DIFS, and waitsfor a further random backoff period. To further prevent a station fromoccupying the channel continuously and thereby preventing other stationsfrom accessing the channel, after a successful transmission, a stationperforms a random backoff before transmitting again.

The PIFS is used to gain priority access to the medium, and is shorterthan the DIFS duration. As one example, PIFS may be used by stationsoperating under point coordination function (PCF) to transmit BeaconFrames with priority. At the nominal beginning of each Contention-FreePeriod (CFP), the station senses the medium. When the medium isdetermined to be idle for one PIFS period (generally 25 μs), the stationtransmits a Beacon frame containing the CF Parameter Set element and adelivery traffic indication message element.

LTE has traditionally used dedicated frequency spectrum. An advantage ofdedicated spectrum is that an LTE system does not need to coexist withother non-3GPP radio access technologies in the same spectrum, which canmaximize spectrum efficiency. The spectrum allocated to LTE, however, islimited. It may not meet the ever increasing demand for largerthroughput from applications/services. Therefore, 3GPP also specifieshow LTE may use unlicensed spectrum in addition to licensed spectrum.

FIG. 6 illustrates a user equipment with license assisted access tounlicensed spectrum. In license assisted access, a UE is connected to aPCell in the licensed band and one or more SCells in the unlicensedband. A secondary cell in unlicensed spectrum may be referred to as aLAA secondary cell (LAA SCell). The LAA SCell may operate indownlink-only mode or operate with both uplink and downlink traffic. Insome scenarios, LTE nodes may operate in standalone mode inlicense-exempt channels without assistance from a licensed cell.

Unlicensed spectrum can, by definition, be used simultaneously bymultiple different technologies. Therefore, LAA must coexist andcooperate with other systems, such as IEEE 802.11 (Wi-Fi). To coexistfairly with a Wi-Fi system, transmission on the SCell conforms to LBTprotocols to avoid collisions which may cause severe interference toon-going transmissions. This includes both performing LBT beforecommencing transmissions, and limiting the maximum duration of a singletransmission burst. The maximum transmission burst duration is specifiedby country and region-specific regulations (e.g., 4 ms in Japan and 13ms according to EN 301.893).

FIG. 7 illustrates an example of license assisted access to unlicensedspectrum using LTE carrier aggregation and listen-before-talk. FIG. 7illustrates five example transmission bursts on an LAA SCell. Eachtransmission burst is constrained by a maximum allowed transmissionduration of 4 ms. Before each LAA SCell transmission is a listeningperiod. The example 8 ms burst is divided into two 4 ms bursts with alistening period before each.

Uplink transmissions are also supported on an LAA SCell. In oneapproach, a UE follows an LBT protocol to attempt channel access afterreceiving the uplink transmission scheduling command.

FIG. 8 illustrates an example of uplink license assisted accesstransmissions based on an uplink listen-before-talk protocol. Theillustrated example divides an 8 ms occupancy time into 4 ms fordownlink channel occupancy and 4 ms for uplink channel occupancy. Afterreceiving a downlink transmission in subframes n−4 to n−1 (i.e., 4 ms),the UE performs a clear channel access for the uplink at subframe n. Ifthe channel is clear, the UE transmits in uplink for subframes n to n+3(i.e., 4 ms).

In another approach, the UE does not follow any LBT protocol to initiatechannel access after receiving an uplink transmission schedulingcommand. LBT and CCA are performed by the eNB before the start ofdownlink transmissions. This may be referred to as a reverse directiongrant protocol.

FIG. 9 illustrates an example of uplink license-assisted accesstransmissions based on a reverse direction grant protocol. Theillustrated example divides an 8 ms occupancy time into 4 ms fordownlink channel occupancy and 4 ms for uplink channel occupancy. Afterreceiving a downlink transmission in subframes n−4 to n−1 (i.e., 4 ms),the UE transmits in uplink for subframes n to n+3 (i.e., 4 ms) withoutperforming a CCA.

Various scheduling problems arise with LAA. For example, determiningwhen an LTE node may access the unlicensed band is unpredictable. Also,coexisting Wi-Fi nodes operating on the same carrier in unlicensed bandsoperate asynchronously and thus they may start and stop transmissions atany time. Both of these factors will put LAA at a significantdisadvantage if it were to use any of the currently defined LTE framestructures for downlink and uplink transmissions that require particularframes to have downlink transmissions and other frames to have uplinktransmissions. If any of the fixed frame structure types 1 or 2 is used,then each subframe is pre-determined to be downlink, uplink or a specialsubframe that carries both downlink and uplink transmissions.

Even if a flexible subframe structure that allows some variations amongthese fixed subframe types is used, such as eIMTA, particular subframesstill are pre-determined to be downlink, uplink, or a special subframe.If channel access is not gained in these particular subframes, theinflexibility of these structures can lead to additional delays,particularly at high loads. Such inflexibility could cause LAA to be anundesirable network configuration because of slow adaptability tointerference and/or traffic demands.

Thus, LAA should have the flexibility for any subframe to carry at leastdownlink or uplink transmissions. Thus, conventional LTE framestructures are not applicable to LAA because LAA should have moreflexibility than the conventional frame structures allow. Any subframecan be part of a downlink transmission burst or an uplink transmissionburst. Generally, two classes of solutions exist for enabling a subframeto be part of a downlink transmission burst or an uplink transmissionburst.

In one class of solutions, the UP determines the subframe formatimplicitly by assuming that every subframe is a downlink subframe unlessexplicitly signaled either via scheduling commands or other means. Ineach subframe that is assumed to be a downlink subframe, the UEdetermines whether the subframe contains any downlink transmissions byeither decoding a successful control message (e.g., (E)PDCCH) or bydetecting a reference signal (e.g., CRS). This class of solutions doesnot restrict the configuration of discontinuous reception (DRX) cyclesfor UEs. Scheduling can be fully dynamic on a subframe basis. Apotential restriction may be the need for a special subframe or ashortened downlink subframe when a downlink transmission burst isfollowed by an uplink transmission burst from UEs in the same cell asthe downlink transmission burst. A benefit is that the UE does not needto have any knowledge of the type of transmissions in future subframeseven when a downlink subframe is successfully detected or an uplinktransmission is made in an uplink subframe that has been successfullyscheduled. These solutions may apply for half-duplex UEs as well,although uplink and downlink are on different frequencies.

In another class of solutions, the UE detects the start of a downlinktransmission burst and the configuration of succeeding subframes in thedownlink transmission burst and any following uplink transmission burstis explicitly indicated to the UE. This enables the UE to receive thesubsequent subframes without performing any detection of signals on asubframe by subframe basis. The last subframe in the downlinktransmission burst, when it is followed by an uplink transmission burstfrom UEs in the same cell as the downlink transmission burst, may stillneed a special subframe or a shortened downlink subframe as is the casewith the first class of solutions. The UE still needs to perform blinddecodes on (E)PDCCH to detect whether a (E)PDSCH is scheduled for thedownlink subframes, similar to the first class of solutions.

DRX operation is important for conserving power consumption. Thus, usinga conventional DRX framework for LAA is beneficial. Under thisframework, using short DRX cycles, an eNB has the flexibility toconfigure UEs so that they can turn on in any particular subframe andsearch for downlink transmissions. This enables the eNB to spread the onperiod of the DRX cycles for the UEs connected to the cell evenly intime so that resources on the carrier can be used in a power efficientmanner. Because a UE simply determines the status of each subframeseparately, any UE can be configured to turn on from its DRX cycle atany time.

In the second class of solutions, the on periods of the short DRX cyclesfor many more UEs would need to be grouped together so that the UEs donot miss the signaling at the beginning of the downlink transmissionburst that indicates the composition of the transmission burst and anyfollowing uplink transmission burst. Thus, a UE may have to spend morepower keeping its receiver chain on just to be able to detect the startof the downlink transmission burst. Although the scheduler in the basestation may know or determine in advance whether downlink or uplinktraffic exists, and may determine whether to schedule a particular UE indownlink for certain time period, such information is not available tothe UE. Thus, the UE keeps its receiver chain for a given carrier openalthough it will not receive any downlink traffic.

SUMMARY

The embodiments described herein include a network node that transmitsinformation about subsequent downlink and uplink subframes to its servedwireless devices to enable scheduling flexibility and to provideaccurate updates of such information. For example, a network node maydetermine, based on its buffer status, that it will transmit aparticular number of downlink subframes and signal to a wireless devicethat it will transmit in the downlink in the next n subframes. Ifadditional downlink data arrives at the network node, the network nodemay determine it will transmit additional downlink subframes and signalto the wireless device that it will transmit in the downlink in the nextx subframes. If a wireless device requests uplink transmissionpermission, the network node may determine how many downlinktransmission subframes remain and determine that the next y subframesafter the downlink subframes will be uplink subframes. The network nodemay signal this updated information to the wireless device. Particularembodiments may apply to operations on the licensed spectrum, unlicensedspectrum, or licensed shared spectrum.

According to some embodiments, a method in a network node comprisesdetermining a first uplink/downlink scheduling pattern for a firstplurality of consecutive subframes; transmitting the firstuplink/downlink scheduling pattern to a wireless device; transmitting atleast one subframe to the wireless device according to the firstuplink/downlink scheduling pattern; determining a second uplink/downlinkscheduling pattern for a second plurality of consecutive subframes,wherein the first plurality of consecutive subframes and the secondplurality of consecutive subframes share at least one subframe; andtransmitting the second uplink/downlink scheduling pattern to thewireless device.

In particular embodiments, the first uplink/downlink scheduling patterncomprises a first value representing a number of downlink subframes inthe first plurality of consecutive subframes, and a second valuerepresenting a number of uplink subframes in the first plurality ofconsecutive subframes. In other embodiments, the first uplink/downlinkscheduling pattern comprises at least one of a set of subframes in thefirst plurality of subframes that the wireless device does not monitorfor downlink, or a set of subframes in the first plurality of subframesthat the wireless device does monitor for downlink.

In particular embodiments, transmitting the first uplink/downlinkscheduling pattern to the wireless device comprises transmitting thefirst uplink/downlink scheduling pattern in a long term evolution (LTE)physical downlink control channel (PDCCH), enhanced physical downlinkcontrol channel (EPDCCH), or physical control format indicator channel(PCFICH).

In particular embodiments, the network node serves a first cell and thefirst uplink/downlink scheduling pattern applies to a second celldifferent from the first cell.

According to some embodiments, a method in a wireless device comprisesreceiving, from a network node, a first uplink/downlink schedulingpattern for a first plurality of consecutive subframes; receiving atleast one subframe according to the first uplink/downlink schedulingpattern; and receiving, from the network node, a second uplink/downlinkscheduling pattern for a second plurality of consecutive subframes,wherein the first plurality of consecutive subframes and the secondplurality of consecutive subframes share at least one subframe.

In particular embodiments, the first uplink/downlink scheduling patterncomprises a first value representing a number of downlink subframes inthe first plurality of consecutive subframes, and a second valuerepresenting a number of uplink subframes in the first plurality ofconsecutive subframes. In other embodiments, the first uplink/downlinkscheduling pattern comprises at least one of a set of subframes in thefirst plurality of subframes that the wireless device does not monitorfor downlink, and a set of subframes in the first plurality of subframesthat the wireless device does monitor for downlink.

In particular embodiments, receiving the first uplink/downlinkscheduling pattern from the network node comprises receiving the firstuplink/downlink scheduling pattern in a LTE PDCCH, EPDCCH, or PCFICH.

In particular embodiments, the network node serves a first cell and thefirst uplink/downlink scheduling pattern applies to a second celldifferent from the first cell.

According to some embodiments, a network node comprises a processor anda memory. The processor is operable to determine a first uplink/downlinkscheduling pattern for a first plurality of consecutive subframes;transmit the first uplink/downlink scheduling pattern to a wirelessdevice; transmit at least one subframe to the wireless device accordingto the first uplink/downlink scheduling pattern; determine a seconduplink/downlink scheduling pattern for a second plurality of consecutivesubframes, wherein the first plurality of consecutive subframes and thesecond plurality of consecutive subframes share at least one subframe;and transmit the second uplink/downlink scheduling pattern to thewireless device.

According to some embodiments, a wireless device comprises a processorand a memory. The processor is operable to receive, from a network node,a first uplink/downlink scheduling pattern for a first plurality ofconsecutive subframes; receive at least one subframe according to thefirst uplink/downlink scheduling pattern; and receive, from the networknode, a second uplink/downlink scheduling pattern for a second pluralityof consecutive subframes, wherein the first plurality of consecutivesubframes and the second plurality of consecutive subframes share atleast one subframe.

According to some embodiments, a network node comprises a determiningmodule and a transmitting module. The determining module is operable todetermine a first uplink/downlink scheduling pattern for a firstplurality of consecutive subframes. The transmitting module is operableto transmit the first uplink/downlink scheduling pattern to a wirelessdevice, and transmit at least one subframe to the wireless deviceaccording to the first uplink/downlink scheduling pattern. Thedetermining module is further operable to determine a seconduplink/downlink scheduling pattern for a second plurality of consecutivesubframes, wherein the first plurality of consecutive subframes and thesecond plurality of consecutive subframes share at least one subframe.The transmitting module is further operable to transmit the seconduplink/downlink scheduling pattern to the wireless device.

According to some embodiments, a wireless device comprises a patternreceiving module and a subframe receiving module. The pattern receivingmodule is operable to receive, from a network node, a firstuplink/downlink scheduling pattern for a first plurality of consecutivesubframes. The subframe receiving module is operable to receive at leastone subframe according to the first uplink/downlink scheduling pattern.The pattern receiving module is further operable to receive, from thenetwork node, a second uplink/downlink scheduling pattern for a secondplurality of consecutive subframes, wherein the first plurality ofconsecutive subframes and the second plurality of consecutive subframesshare at least one subframe.

Also disclosed is a computer program product. The computer programproduct comprises instructions stored on non-transient computer-readablemedia which, when executed by a processor, perform the acts determininga first uplink/downlink scheduling pattern for a first plurality ofconsecutive subframes; transmitting the first uplink/downlink schedulingpattern to a wireless device; transmitting at least one subframe to thewireless device according to the first uplink/downlink schedulingpattern; determining a second uplink/downlink scheduling pattern for asecond plurality of consecutive subframes, wherein the first pluralityof consecutive subframes and the second plurality of consecutivesubframes share at least one subframe; and transmitting the seconduplink/downlink scheduling pattern to the wireless device.

Another computer program product comprises instructions stored onnon-transient computer-readable media which, when executed by aprocessor, perform the acts of receiving, from a network node, a firstuplink/downlink scheduling pattern for a first plurality of consecutivesubframes; receiving at least one subframe according to the firstuplink/downlink scheduling pattern; and receiving, from the networknode, a second uplink/downlink scheduling pattern for a second pluralityof consecutive subframes, wherein the first plurality of consecutivesubframes and the second plurality of consecutive subframes share atleast one subframe.

Particular embodiments may exhibit some of the following technicaladvantages. Particular embodiments provide scheduling flexibility, whichimproves network efficiency (e.g., efficient bandwidth usage) andprovides adaptability to interference and/or traffic demands. Problemsassociated with fixing a scheduling pattern at the beginning of a longtransmission burst may be avoided. Particular embodiments conserve powerand battery life by not requiring all wireless devices to wake up fromdiscontinuous reception mode and search for the specific point wherescheduling information is received. Other technical advantages will bereadily apparent to one skilled in the art from the following figures,description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the embodiments and their featuresand advantages, reference is now made to the following description,taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates an example Orthogonal Frequency-Division Multiplexed(OFDM) symbol;

FIG. 2 illustrates an example radio frame;

FIG. 3 illustrates an example downlink subframe;

FIG. 4 illustrates an example of carrier aggregation;

FIG. 5 illustrates an example WLAN listen-before-talk mechanism;

FIG. 6 illustrates a user equipment with license assisted access tounlicensed spectrum;

FIG. 7 illustrates an example of license assisted access to unlicensedspectrum using LTE carrier aggregation and listen-before-talk;

FIG. 8 illustrates an example of uplink license assisted accesstransmissions based on an uplink listen-before-talk protocol;

FIG. 9 illustrates an example of uplink license assisted accesstransmissions based on a reverse direction grant protocol;

FIG. 10 is a block diagram illustrating an example wireless network,according to a particular embodiment;

FIG. 11 is a flow diagram illustrating an example method in a networknode of scheduling an uplink/downlink pattern for subframes, accordingto some embodiments;

FIG. 12 is a flow diagram illustrating an example method in a wirelessdevice of receiving an uplink/downlink pattern for subframes, accordingto some embodiments;

FIG. 13A is a block diagram illustrating an example embodiment of awireless device;

FIG. 13B is a block diagram illustrating example components of awireless device;

FIG. 14A is a block diagram illustrating an example embodiment of anetwork node; and

FIG. 14B is a block diagram illustrating example components of a networknode.

DETAILED DESCRIPTION

Because access to unlicensed bands is unpredictable (e.g., based onlisten-before talk (LBT) protocols) and Wi-Fi nodes operating on theunlicensed bands operate asynchronously, license assisted access (LAA)may not operate efficiently using conventional fixed format LTE framestructures for downlink and uplink transmissions. When using a fixedformat, if channel access is not gained in the predetermined subframes,then transmission delays may result, particularly at high loads.

An object of the present disclosure is to obviate at least thedisadvantages above and provide LAA the flexibility for any subframe toinclude downlink or uplink transmissions. The embodiments describedherein include a network node that transmits information aboutsubsequent downlink and uplink subframes to its served wireless devicesto enable scheduling flexibility and to provide accurate updates of suchinformation. Embodiments also include a wireless device operable toreceive flexible uplink and downlink scheduling information and toreceive or transmit subframes according to the flexible uplink/downlinkpattern.

Thus, particular embodiments provide scheduling flexibility, whichimproves network efficiency and provides adaptability to interferenceand/or traffic demands. Particular embodiments conserve power andbattery life by not requiring all wireless devices to wake up fromdiscontinuous reception mode and search for the specific point wherescheduling information is received.

The following description sets forth numerous specific details. It isunderstood, however, that embodiments may be practiced without thesespecific details. In other instances, well-known circuits, structuresand techniques have not been shown in detail in order not to obscure theunderstanding of this description. Those of ordinary skill in the art,with the included descriptions, will be able to implement appropriatefunctionality without undue experimentation.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to implement such feature, structure, orcharacteristic in connection with other embodiments, whether or notexplicitly described.

Particular embodiments are described with reference to FIGS. 10-14B ofthe drawings, like numerals being used for like and corresponding partsof the various drawings. LTE is used throughout this disclosure as anexample cellular system, but the ideas presented herein may apply toother wireless communication systems as well.

FIG. 10 is a block diagram illustrating an example wireless network,according to a particular embodiment. Wireless network 100 includes oneor more wireless devices 110 (such as mobile phones, smart phones,laptop computers, tablet computers, MTC devices, or any other devicesthat can provide wireless communication) and a plurality of networknodes 120 (such as base stations or eNodeBs). Wireless device 110 mayalso be referred to as a UE. Radio network node 120 serves coverage area115 (also referred to as cell 115).

In general, wireless devices 110 that are within coverage of radionetwork node 120 (e.g., within cell 115 served by network node 120)communicate with radio network node 120 by transmitting and receivingwireless signals 130. For example, wireless devices 110 and radionetwork node 120 may communicate wireless signals 130 containing voicetraffic, data traffic, and/or control signals. A network node 120communicating voice traffic, data traffic, and/or control signals towireless device 110 may be referred to as a serving network node 120 forthe wireless device 110. Wireless signals 130 may include both downlinktransmissions (from radio network node 120 to wireless devices 110) anduplink transmissions (from wireless devices 110 to radio network node120).

Wireless signals 130 may include frames and subframes, such as thosedescribed with respect to FIGS. 1-3. Network node 120 may dynamicallyschedule subframes as an uplink subframe, a downlink subframe, or acombination uplink and downlink subframe.

Network node 120 may operate in a licensed frequency spectrum, such asan LTE spectrum. Network node 120 may also operate in an unlicensedfrequency spectrum, such as a 5 GHz Wi-Fi spectrum. In an unlicensedfrequency spectrum, network node 120 may coexist with other devices suchas IEEE 802.11 access points and terminals. To share the unlicensedspectrum, network node 120 may perform LBT protocols before transmittingor receiving wireless signals 130. Wireless device 110 may also operatein one or both of licensed or unlicensed spectrum and in someembodiments may also perform LBT protocols before transmitting wirelesssignals 130. Both network node 120 and wireless device 110 may alsooperate in licensed shared spectrum.

For example, network node 120 a may operate in a licensed spectrum andnetwork node 120 b may operate in an unlicensed spectrum. Wirelessdevice 110 may operate in both licensed and unlicensed spectrum. Inparticular embodiments, network nodes 120 a and 120 b may beconfigurable to operate in a licensed spectrum, an unlicensed spectrum,a licensed shared spectrum, or any combination. Although the coveragearea of cell 115 b is illustrated as included in the coverage area ofcell 115 a, in particular embodiments the coverage areas of cells 115 aand 115 b may overlap partially, or may not overlap at all.

Each network node 120 may have a single transmitter or multipletransmitters for transmitting signals 130 to wireless devices 110. Insome embodiments, network node 120 may comprise a multi-inputmulti-output (MIMO) system. Similarly, each wireless device 110 may havea single receiver or multiple receivers for receiving signals 130 fromnetwork nodes 120 or other wireless devices 110.

In particular embodiments, wireless device 110 and network nodes 120 mayperform carrier aggregation. For example, network node 120 a may servewireless device 110 as a PCell and network node 120 b may serve wirelessdevice 110 as a SCell. Network nodes 120 may perform self-scheduling orcross-scheduling. If network node 120 a is operating in licensedspectrum and network node 120 b is operating in unlicensed spectrum,network node 120 a may provide license assisted access to the unlicensedspectrum (i.e., network node 120 a is a LAA PCell and network node 120 bis a LAA SCell).

In particular embodiments, network node 120 a may dynamically scheduleuplink and downlink subframes for wireless device 110. For example, inparticular embodiments network node 120 a may determine a firstuplink/downlink scheduling pattern for a first plurality of consecutivesubframes. Network node 120 a may transmit the first uplink/downlinkscheduling pattern to wireless device 110 (e.g., using (E)PDCCH) andtransmit at least one subframe to wireless device 110 according to thefirst uplink/downlink scheduling pattern.

If network node 120 a received additional downlink data, or a requestfor uplink transmission from a wireless device, for example, thennetwork node 120 a may determine a second uplink/downlink schedulingpattern for a second plurality of consecutive subframes. Network node120 a may transmit the second uplink/downlink scheduling pattern towireless device 110 in any of the subframes previously scheduled forwireless device 110.

In particular embodiments, the uplink/downlink scheduling pattern maycomprise a number of subsequent downlink subframes, a number ofsubsequent downlink and uplink subframes, an indication of whichsubframes to monitor or not monitor for downlink, or any other suitablepattern. Other embodiments with respect to network nodes are describedin more detail below.

In particular embodiments, wireless device 110 may receive, from networknode 120 (e.g., using (E)PDCCH), a first uplink/downlink schedulingpattern for a first plurality of consecutive subframes. Wireless device110 may receive at least one subframe according to the firstuplink/downlink scheduling pattern. In one of the scheduled downlinksubframes, wireless device 110 may receive a second uplink/downlinkscheduling pattern for a second plurality of consecutive subframes.Other embodiments with respect to wireless devices are described in moredetail below.

Although particular embodiments are described with respect to licensedor unlicensed spectrum, license assisted access, and/or carrieraggregation, the embodiments described herein apply equally to dynamicuplink and downlink scheduling in any spectrum and with respect to asingle cell or any combination of cells.

In wireless network 100, each radio network node 120 may use anysuitable radio access technology, such as long term evolution (LTE),LTE-Advanced, UMTS, HSPA, GSM, cdma2000, WiMax, WiFi, and/or othersuitable radio access technology. Wireless network 100 may include anysuitable combination of one or more radio access technologies. Forpurposes of example, various embodiments may be described within thecontext of certain radio access technologies. However, the scope of thedisclosure is not limited to the examples and other embodiments coulduse different radio access technologies.

As described above, embodiments of a wireless network may include one ormore wireless devices and one or more different types of radio networknodes capable of communicating with the wireless devices. The networkmay also include any additional elements suitable to supportcommunication between wireless devices or between a wireless device andanother communication device (such as a landline telephone). A wirelessdevice may include any suitable combination of hardware and/or software.For example, in particular embodiments, a wireless device, such aswireless device 110, may include the components described with respectto FIG. 13A below. Similarly, a network node may include any suitablecombination of hardware and/or software. For example, in particularembodiments, a network node, such as network node 120, may include thecomponents described with respect to FIG. 14A below.

The following embodiments describe a network node that transmitsinformation about subsequent downlink and uplink subframes to a servedwireless device to enable scheduling flexibility and to provide accurateupdates of such information. Following the general descriptions aredescriptions of example methods in a network node and example methods ina wireless device.

In some embodiments, a network node transmits subsequent downlink anduplink subframe information in a PDCCH or an EPDCCH. The information mayinclude two numerical values representing the number of downlinksubframes and the number of uplink subframes that will follow after thecurrent subframe. In other embodiments, the information may only includedownlink information, such as an explicit number of downlink subframesthat will follow.

For example, in a first subframe n, an eNB may determine to transmit 2downlink and 0 uplink subframes in subsequence based on its currentbuffer status. The eNB may broadcast that it intends to transmit in thedownlink in subframes n+1 and n+2. In other words, the eNB may determineand transmit a first uplink/downlink scheduling pattern (i.e., 2 DL, 0UL) for a first plurality of consecutive subframes (i.e., subframes n+1and n+2).

If additional downlink data arrives at the eNB, for example, the eNB maydetermine to transmit 5 downlink and 0 uplink subframes in subframe n+1.The eNB may broadcast that it intends to transmit in the downlink insubframes n+2, n+3, n+4, n+5 and n+6. In other words, the eNB maydetermine and transmit a second uplink/downlink scheduling pattern(i.e., 5 DL, 0 UL) for a second plurality of consecutive subframes(i.e., subframes n+2, n+3, n+4, n+5 and n+6). The second plurality ofconsecutive subframes shares at least one subframe with the firstplurality of consecutive subframes (i.e., subframe n+2).

The eNB may continue do dynamically update the scheduling of subframesas determined by traffic patterns. For example, if several UEs requestuplink transmission permission, the eNB may determine to transmit 4downlink and 3 uplink subframes in subframe n+2. The eNB may broadcastthat it intends to transmit in the downlink in subframe n+3, n+4, n+5and n+6 after which UEs are scheduled to transmit in the uplink insubframes n+7, n-+8 and n+9.

In particular embodiments, a network node may transmit the schedulinginformation on a PCell, a SCell, or a LAA SCell, for example. One(E)PDCCH may also carry the subsequent downlink and uplink subframeinformation for the PCell, or for one or more SCells (e.g., for one ormore LAA SCells for operation on an unlicensed spectrum). The schedulinginformation may be self-scheduled or cross-scheduled.

In some embodiments, a network node may use broadcast or dedicatedsignaling to inform a wireless device whether the wireless device shouldmonitor particular downlink subframes. More generally, a network nodemay provide a wireless device with a variety of information that mayresult in the same dynamic scheduling described above. For example, inparticular embodiments a network node may provide a set (or window) ofcoming uplink subframes. A network node may provide a set (or window) ofcoming downlink subframes. In particular embodiments, a network node mayprovide a set (or window) of subframes for which the wireless devicedoes not need to monitor in downlink. A network node may provide a set(or window) of subframes for which the wireless device does need tomonitor in downlink. In the embodiments that specify a set or window ofsubframes, the set or window of subframes may start from the point thewireless device receives the information or be offset in time by a givenconstant (e.g., number of subframes, number of ms, etc.). As describedabove, the scheduling information may be sent on a PCell, SCell, LAASCell, self-scheduled, cross-scheduled, etc.

In some embodiments, for wireless devices in active time (i.e., not inDRX), the wireless device may conserve power by determining when not tomonitor the subframes for downlink. For example, a wireless device maybe informed that a network node has scheduled other wireless devices inuplink for a given point of time, or that the network node does notintend to transmit for a given time in downlink.

In particular embodiments, a network node may inform the wireless deviceusing PDCCH. For example, the network node may transmit a DCI message onthe PDCCH within the common search space to inform wireless devices whenthe network node will shift to uplink, or not transmit anything more ona given cell (e.g., an LAA SCell). The network node may transmit theinformation with a specific RNTI. The RNTI may, for example, be LAA-RNTIin case of an LAA SCell. If a wireless device does not receive the DCImessage, the wireless device may assume it should monitor the applicablesubframes for downlink as long as the wireless device is not scheduledfor uplink, in which case it will transmit in uplink. In particularembodiments, the PCell and other cell identities for a wireless devicemay be wireless device specific. Thus, particular embodiments may definea common form of information to identify cells across wireless devices.Particular embodiments may extend the same solution to EPDCCH bydefining a common search space on EPDCCH so that multiple wirelessdevices may share the same search space.

Other embodiments may transmit a control channel on each cell, forexample on each LAA SCell, that can be received by all wireless devicesthat includes the scheduling information described above. For example,such signaling might reuse PCFICH. Instead of indicating the endingposition of PDCCH and the starting position of PDSCH, the PCFICH mayindicate whether the wireless device should monitor the next subframesin downlink. PCFICH is able to indicate four values. In particularembodiments, one value may indicate that the next subframe should bemonitored in downlink, and the other three values may indicate ranges ofsubframes that should not be monitored in downlink.

Particular embodiments may include wireless device with a detector todetermine whether the signal is present. If the signal is not detected,the next subframe may be monitored in downlink by the wireless device ifthe wireless device does not go in DRX.

In some embodiments, a network node may use signaling specific to awireless device the enables the wireless device to conserve power by notmonitoring subframes for downlink transmission. The signaling may besimilar to the broadcast mechanism targeting wireless devices that arein active time (i.e., not in DRX).

In particular embodiments, the network node may use dedicated signalingto signal a wireless device that the wireless device may conserve powerby not monitoring for downlink transmissions during uplink subframes.For example, if a wireless device knows that particular subframes willbe uplink subframes, the wireless devices that are not assigned with anuplink grant for those subframes can stop monitoring subframes indownlink. As another example, the wireless device may be informed thatit can stop monitoring subframes in downlink for a particular number ofsubframes within a window of upcoming subframes. The window length maydepend on the scheduler and LBT and TXOP.

In particular embodiments, the network node may use dedicated signalingto signal a wireless device that the wireless device may conserve powerby not monitoring for downlink transmissions during downlink subframes.For example, the wireless device may be informed that it may save powerby not monitoring for downlink transmission for a certain number ofsubframes within a window of upcoming subframes. The window length maydepend on the scheduler and LBT and TXOP.

For signaling specific to a wireless device, particular embodiments mayuse either PDCCH or EPDCCH. For example, particular embodiments mayinclude new bits to indicate to a wireless device whether it should notmonitor the downlink subframe(s) within a window of upcoming subframes.The window may start immediately, or with an offset from a DCI message.For an uplink grant, an offset may apply. If the switching point betweendownlink and uplink is in the subframe directly following the uplinkgrant, however, then no offset may be needed. For a downlink assignment,an offset may not be needed. Similar to uplink, if an uplink isscheduled for other wireless devices the downlink assignment may be usedas an offset to indicate the starting point of the window.

In particular embodiments, a message dedicated to a particular wirelessdevice may be sent on either the cell it applies for on another cell. Ifit is sent on another cell, then a cell indicator may be included in themessage. For cross-carrier scheduling, the DCI message may be sent onanother cell, but the indication may be assumed to apply to the cellthat it is targeting.

FIG. 11 is a flow diagram illustrating an example method in a networknode of scheduling an uplink/downlink pattern for subframes, accordingto some embodiments. In particular embodiments, one or mote steps ofFIG. 11 may be performed by network node 120 of wireless network 100described with respect to FIG. 10.

At step 1112, the network node determines a first uplink/downlinkscheduling pattern for a first plurality of consecutive subframes. Forexample, network node 120 a may determine, based on its current bufferstatus, that the first uplink/downlink scheduling pattern comprisestransmitting 2 downlink subframes followed by 0 uplink subframes.

In particular embodiments, the first uplink/downlink scheduling patternmay comprise any of the uplink/downlink scheduling patterns describedabove. For example, the patterns may include a number of downlink ofuplink subframes, a set or window of frames to monitor or not to monitorfor uplink or downlink, or any suitable combination of patterns.

At step 1114, the network node transmits the first uplink/downlinkscheduling pattern to a wireless device. For example, network node 120 amay transmit to wireless device 110 a pattern indicating that subframesn+1 and n+2 are downlink subframes. In particular embodiments, thenetwork node may use any of the broadcast or dedicated signaling methodsdescribed above to transmit the uplink/downlink scheduling pattern. Someembodiments may use any one or more of a PDCCH, EPDCCH, or PCFICH.

At step 1116, the network node transmits at least one subframe to thewireless device according to the first uplink/downlink schedulingpattern. For example, network node 120 a may transmit downlink subframen+1 to wireless device 110. In particular embodiments, such asembodiments using cross-scheduling, a different network node maytransmit the subframes to the wireless device according to thescheduling pattern.

At step 1118, the network node determine a second uplink/downlinkscheduling pattern for a second plurality of consecutive subframes,wherein the first plurality of consecutive subframes and the secondplurality of consecutive subframes share at least one subframe. Forexample, network node 120 a may determine, based on additional downlinkdata, to transmit 5 downlink and 0 uplink subframes in subframe n+1. Inthis example, the second plurality of consecutive subframes (i.e.,subframes n+2, n+3, n+4, n+5 and n+6) shares at least one subframe withthe first plurality of consecutive subframes (i.e., subframe n+2).

At step 1120, the network node transmits the second uplink/downlinkscheduling pattern to the wireless device. For example, network node 120a may transmit to wireless device 110 a pattern indicating thatsubframes n+2, n+3, n+4, n+5 and n+6 are downlink subframes. Inparticular embodiments, the network node may use any of the broadcast ordedicated signaling methods described above to transmit theuplink/downlink scheduling pattern.

Modifications, additions, or omissions may be made to method 1100.Additionally, one or more steps in method 1100 of FIG. 11 may beperformed in parallel or in any suitable order. All or parts of method1100 may be repeated over time as necessary.

FIG. 12 is a flow diagram illustrating an example method in a wirelessdevice of receiving an uplink/downlink pattern for subframes, accordingto some embodiments. In particular embodiments, one or more steps ofFIG. 11 may be performed by network node 120 of wireless network 100described with respect to FIG. 10.

At step 1212, the wireless device receives, from a network node, a firstuplink/downlink scheduling pattern for a first plurality of consecutivesubframes. For example, wireless device 110 may receive, from networknode 120 a, a first uplink/downlink scheduling pattern indicating thatsubframes n+1 and n+2 are downlink subframes. In particular embodiments,the wireless device receive the uplink/downlink scheduling patternaccording to any of the broadcast or dedicated signaling methodsdescribed above. Some embodiments may use any one or more of a PDCCH,EPDCCH, or PCFICH. The uplink/downlink scheduling pattern may compriseany of the patterns described above.

At step 1214, the wireless device receives at least one subframeaccording to the first uplink/downlink scheduling pattern. For example,wireless device 110 may receive downlink subframe n+2.

At step 1216, the wireless device receives, from the network node, asecond uplink/downlink scheduling pattern for a second plurality ofconsecutive subframes, wherein the first plurality of consecutivesubframes and the second plurality of consecutive subframes share atleast one subframe. For example, wireless device 110 may receive, fromnetwork node 120 a, a second uplink/downlink scheduling patternindicating that subframes n+2, n+3, n+4, n+5 and n+6 are downlinksubframes. In this example, the second plurality of consecutivesubframes (i.e., subframes n+2, n+3, n+4, n+5 and n+6) shares at leastone subframe with the first plurality of consecutive subframes (i.e.,subframe n+2).

Modifications, additions, or omissions may be made to method 1200.Additionally, one or more steps in method 1200 of FIG. 12 may beperformed in parallel or in any suitable order. All or parts of method1200 may be repeated over time as necessary.

FIG. 13A is a block diagram illustrating an example embodiment of awireless device. The wireless device is an example of wireless device110 illustrated in FIG. 10. The wireless device is operable to receive afirst uplink/downlink scheduling pattern for a first plurality ofconsecutive subframes. The wireless device is further operable toreceive at least one subframe according to the first uplink/downlinkscheduling pattern. The wireless device is also operable to receive asecond uplink/downlink scheduling pattern for a second plurality ofconsecutive subframes, wherein the first plurality of consecutivesubframes and the second plurality of consecutive subframes share atleast one subframe.

Particular examples of a wireless device include a mobile phone, a smartphone, a PDA (Personal Digital Assistant), a portable computer (e.g.,laptop, tablet), a sensor, a modem, a machine type (MTC) device/machineto machine (M2M) device, laptop embedded equipment (LEE), laptop mountedequipment (LME), USB dongles, a device-to-device capable device, avehicle-to-vehicle device, or any other device that can provide wirelesscommunication. The wireless device includes transceiver 1310, processor1320, and memory 1330. In some embodiments, transceiver 1310 facilitatestransmitting wireless signals to and receiving wireless signals fromwireless network node 120 (e.g., via an antenna), processor 1320executes instructions to provide some or all of the functionalitydescribed herein as provided by the wireless device, and memory 1330stores the instructions executed by processor 1320.

Processor 1320 includes any suitable combination of hardware andsoftware implemented in one or more integrated circuits or modules toexecute instructions and manipulate data to perform some or all of thedescribed functions of the wireless device. In some embodiments,processor 1320 may include, for example, one or more computers, one moreprogrammable logic devices, one or more central processing units (CPUs),one or more microprocessors, one or more applications, and/or otherlogic, and/or any suitable combination of the preceding. Processor 1320may include analog and/or digital circuitry configured to perform someor all of the described functions of wireless device 110. For example,processor 1320 may include resistors, capacitors, inductors,transistors, diodes, and/or any other suitable circuit components.

Memory 1330 is generally operable to store computer executable code anddata. Examples of memory 1330 include computer memory (e.g., RandomAccess Memory (RAM) or Read Only Memory (ROM)), mass storage media(e.g., a hard disk), removable storage media (e.g., a Compact Disk (CD)or a Digital Video Disk (DVD)), and/or or any other volatile ornon-volatile, non-transitory computer-readable and/orcomputer-executable memory devices that store information.

In particular embodiments, processor 1320 in communication withtransceiver 1310 receives a first uplink/downlink scheduling pattern fora first plurality of consecutive subframes; receives at least onesubframe according to the first uplink/downlink scheduling pattern; andreceives a second uplink/downlink scheduling pattern for a secondplurality of consecutive subframes.

Other embodiments of the wireless device may include additionalcomponents (beyond those shown in FIG. 13A) responsible for providingcertain aspects of the wireless device's functionality, including any ofthe functionality described above and/or any additional functionality(including any functionality necessary to support the solution describedabove).

FIG. 13B is a block diagram illustrating example components of awireless device 110. The components may include pattern receiving module1350 and subframe receiving module 1352.

Pattern receiving module 1350 may perform the pattern receivingfunctions of wireless device 110. For example, pattern receiving module1350 may receive a first and second uplink/downlink scheduling patternfor a first and second plurality of consecutive subframes. In certainembodiments, pattern receiving module 1350 may include or be included inprocessor 1320. Pattern receiving module 1350 may include circuitryconfigured to receive radio signals. In particular embodiments, patternreceiving module 1350 may communicate with subframe receiving module1352.

Subframe receiving module 1352 may perform the subframe receivingfunctions of wireless device 110. For example, subframe receiving module1352 may receive a subframe according to the first or seconduplink/downlink scheduling pattern. In certain embodiments, subframereceiving module 1352 may include or be included in processor 1320.Subframe receiving module 1352 may include circuitry configured toreceive radio signals. In particular embodiments, subframe receivingmodule 1352 may communicate with pattern receiving module 1350.

FIG. 14A is a block diagram illustrating an example embodiment of anetwork node. The network node is an example of the network node 120illustrated in FIG. 10. The network node is operable to determine afirst uplink/downlink scheduling pattern for a first plurality ofconsecutive subframes and transmit the first uplink/downlink schedulingpattern to a wireless device. The network node is further operable totransmit at least one subframe to the wireless device according to thefirst uplink/downlink scheduling pattern. The network node is alsooperable to determine a second uplink/downlink scheduling pattern for asecond plurality of consecutive subframes, wherein the first pluralityof consecutive subframes and the second plurality of consecutivesubframes share at least one subframe, and transmit the seconduplink/downlink scheduling pattern to the wireless device.

Network node 120 can be an eNodeB, a nodeB, a base station, a wirelessaccess point (e.g., a Wi-Fi access point), a low power node, a basetransceiver station (BTS), a transmission point or node, a remote RFunit (RRU), a remote radio head (RRH), or other radio access node.Network node 120 includes at least one transceiver 1410, at least oneprocessor 1420, at least one memory 1430, and at least one networkinterface 1440. Transceiver 1410 facilitates transmitting wirelesssignals to and receiving wireless signals from a wireless device, suchas wireless devices 110 (e.g., via an antenna); processor 1420 executesinstructions to provide some or all of the functionality described aboveas being provided by a network node 120; memory 1430 stores theinstructions executed by processor 1420; and network interface 1440communicates signals to backend network components, such as a gateway,switch, router, Internet, Public Switched Telephone Network (PSTN),controller, and/or other network nodes 120. Processor 1420 and memory1430 can be of the same types as described with respect to processor1320 and memory 1330 of FIG. 13A above.

In some embodiments, network interface 1440 is communicatively coupledto processor 1420 and refers to any suitable device operable to receiveinput for network node 120, send output from network node 120, performsuitable processing of the input or output or both, communicate to otherdevices, or any combination of the preceding. Network interface 1440includes appropriate hardware (e.g., port, modem, network interfacecard, etc.) and software, including protocol conversion and dataprocessing capabilities, to communicate through a network.

In particular embodiments, processor 1420 in communication withtransceiver 1410 determines a first uplink/downlink scheduling patternfor a first plurality of consecutive subframes; transmits the firstuplink/downlink scheduling pattern to a wireless device; transmits atleast one subframe to the wireless device according to the firstuplink/downlink scheduling pattern; determines a second uplink/downlinkscheduling pattern for a second plurality of consecutive subframes; andtransmits the second uplink/downlink scheduling pattern to the wirelessdevice.

Other embodiments of network node 120 include additional components(beyond those shown in FIG. 14A) responsible for providing certainaspects of the network node's functionality, including any of thefunctionality described above and/or any additional functionality(including any functionality necessary to support the solution describedabove). The various different types of radio network nodes may includecomponents having the same physical hardware but configured (e.g., viaprogramming) to support different radio access technologies, or mayrepresent partly or entirely different physical components.

FIG. 14B is a block diagram illustrating example components of a networknode 120. The components may include determining module 1450 andtransmitting module 1452.

Determining module 1450 may perform the determining functions of networknode 120. For example, determining module 1450 may determine a first andsecond uplink/downlink scheduling pattern for a first and secondplurality of consecutive subframes. In certain embodiments,synchronization determining module 1150 may include or be included inprocessor 1420. In particular embodiments, determining module 1450 maycommunicate with transmitting module 1452.

Transmitting module 1452 may perform the transmitting functions ofnetwork node 120. For example, transmitting module 1452 may transmituplink/downlink scheduling patterns and downlink subframes to wirelessdevice 110. In certain embodiments, transmitting module 1452 may includeor be included in processor 1420. Transmitting module 1452 may includecircuitry configured to transmit radio signals. In particularembodiments, transmitting module 1452 may communicate with determiningmodule 1450.

Some embodiments of the disclosure may provide one or more technicaladvantages. As an example, some embodiments provide schedulingflexibility, which improves network efficiency (e.g., efficientbandwidth usage) and provides adaptability to interference and/ortraffic demands. Problems associated with fixing a scheduling pattern atthe beginning of a long transmission burst may be avoided. Particularembodiments conserve power and battery life by not requiring allwireless devices to wake up from discontinuous reception mode and searchfor the specific point where scheduling information is received. Someembodiments may benefit from some, none, or all of these advantages.Other technical advantages may be readily ascertained by one of ordinaryskill in the art.

Modifications, additions, or omissions may be made to the systems andapparatuses disclosed herein without departing from the scope of theinvention. The components of the systems and apparatuses may beintegrated or separated. Moreover, the operations of the systems andapparatuses may be performed by more, fewer, or other components.Additionally, operations of the systems and apparatuses may be performedusing any suitable logic comprising software, hardware, and/or otherlogic. As used in this document, “each” refers to each member of a setor each member of a subset of a set.

Modifications, additions, or omissions may be made to the methodsdisclosed herein without departing from the scope of the invention. Themethods may include more, fewer, or other steps. Additionally, steps maybe performed in any suitable order.

Although this disclosure has been described in terms of certainembodiments, alterations and permutations of the embodiments will beapparent to those skilled in the art. Accordingly, the above descriptionof the embodiments does not constrain this disclosure. Other changes,substitutions, and alterations are possible without departing from thespirit and scope of this disclosure, as defined by the claims below.

Abbreviations used in the preceding description include:

3GPP Third Generation Partnership Project

BTS Base Transceiver Station

CCA Clear Channel Assessment

CFP Contention-Free Period

D2D Device to Device

DCF Distributed Coordination Function

DIFS DCF Inter-frame Spacing

DL Downlink

DRS Discovery Reference Signal

eNB eNodeB

EPDCCH Enhanced Physical Downlink Control Channel

FDD Frequency Division Duplex

LAA Licensed Assisted Access

LBT Listen Before Talk

LTE Long Term Evolution

M2M Machine to Machine

MIMO Multi-Input Multi-Output

MTC Machine Type Communication

OFDM Orthogonal Frequency Division Multiplexing

PCell Primary Cell

PCF Point Coordination Function

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

PIFS PCF Inter-frame Spacing

PUCCH Physical Uplink Control Channel

PUSCH Physical Uplink Shared Channel

RAN Radio Access Network

RAT Radio Access Technology

RRH Remote Radio Head

RRU Remote Radio Unit

SCell Secondary Cell

SeNB Secondary eNodeB

SIFS Short Inter-frame Spacing

TDD Time division duplex

UE User Equipment

WAN Wireless Access Network

The invention claimed is:
 1. A method in a network node, the methodcomprising: determining a first uplink/downlink scheduling pattern for afirst plurality of consecutive subframes based on a traffic pattern ofdata to transmit or receive; transmitting the first uplink/downlinkscheduling pattern to a wireless device; transmitting or receiving atleast one subframe of the first plurality of consecutive subframes to orfrom the wireless device according to the first uplink/downlinkscheduling pattern; determining the traffic pattern of data to transmitor receive has changed; determining, based on the changed trafficpattern, a second uplink/downlink scheduling pattern for a secondplurality of consecutive subframes, wherein the first plurality ofconsecutive subframes and the second plurality of consecutive subframesoverlap in time by at least one shared subframe; transmitting the seconduplink/downlink scheduling pattern to the wireless device; andtransmitting or receiving the at least one shared subframe; wherein thefirst uplink/downlink scheduling pattern comprises at least one of: aset of subframes in the first plurality of subframes that the wirelessdevice does not monitor for downlink; and a set of subframes in thefirst plurality of subframes that the wireless device does monitor fordownlink.
 2. The method of claim 1, wherein transmitting the firstuplink/downlink scheduling pattern to the wireless device comprisestransmitting the first uplink/downlink scheduling pattern in a long termevolution (LTE) physical downlink control channel (PDCCH) or enhancedphysical downlink control channel (EPDCCH).
 3. The method of claim 1,wherein transmitting the first uplink/downlink scheduling pattern to thewireless device comprises transmitting the first uplink/downlinkscheduling pattern in a LTE physical control format indicator channel(PCFICH).
 4. The method of claim 1, wherein the network node serves afirst cell and the first uplink/downlink scheduling pattern applies to asecond cell different from the first cell.
 5. The method of claim 1,wherein the first uplink/downlink scheduling pattern comprises: a firstvalue representing a number of downlink subframes in the first pluralityof consecutive subframes; and a second value representing a number ofuplink subframes in the first plurality of consecutive subframes.
 6. Amethod in a wireless device, the method comprising: receiving, from anetwork node, a first uplink/downlink scheduling pattern for a firstplurality of consecutive subframes; receiving or transmitting at leastone subframe according to the first uplink/downlink scheduling pattern;receiving, from the network node, a second uplink/downlink schedulingpattern for a second plurality of consecutive subframes, wherein thefirst plurality of consecutive subframes and the second plurality ofconsecutive subframes overlap in time by at least one shared subframe;and transmitting or receiving the at least one shared subframe; whereinthe first uplink/downlink scheduling pattern comprises at least one of:a set of subframes in the first plurality of subframes that the wirelessdevice does not monitor for downlink; and a set of subframes in thefirst plurality of subframes that the wireless device does monitor fordownlink.
 7. The method of claim 6, wherein receiving the firstuplink/downlink scheduling pattern from the network node comprisesreceiving the first uplink/downlink scheduling pattern in a long termevolution (LTE) physical downlink control channel (PDCCH) or enhancedphysical downlink control channel (EPDCCH).
 8. The method of claim 6,wherein receiving the first uplink/downlink scheduling pattern from thenetwork node comprises receiving the first uplink/downlink schedulingpattern in a LTE physical control format indicator channel (PCFICH). 9.The method of claim 6, wherein the network node serves a first cell andthe first uplink/downlink scheduling pattern applies to a second celldifferent from the first cell.
 10. The method of claim 6, wherein thefirst uplink/downlink scheduling pattern comprises: a first valuerepresenting a number of downlink subframes in the first plurality ofconsecutive subframes; and a second value representing a number ofuplink subframes in the first plurality of consecutive subframes.
 11. Anetwork node comprising a processor and a memory, the processor operableto: determine a first uplink/downlink scheduling pattern for a firstplurality of consecutive subframes based on a traffic pattern of data totransmit or receive; transmit the first uplink/downlink schedulingpattern to a wireless device; transmit or receive at least one subframeof the first plurality of consecutive subframes to or from the wirelessdevice according to the first uplink/downlink scheduling pattern;determine the traffic pattern of data to transmit or receive haschanged; determine, based on the changed traffic pattern, a seconduplink/downlink scheduling pattern for a second plurality of consecutivesubframes, wherein the first plurality of consecutive subframes and thesecond plurality of consecutive subframes overlap in time by at leastone shared subframe; transmit the second uplink/downlink schedulingpattern to the wireless device; and transmit or receive the at least oneshared subframe; wherein the first uplink/downlink scheduling patterncomprises at least one of: a set of subframes in the first plurality ofsubframes that the wireless device does not monitor for downlink; and aset of subframes in the first plurality of subframes that the wirelessdevice does monitor for downlink.
 12. The network node of claim 11,wherein the processor is operable to transmit the first uplink/downlinkscheduling pattern in a long term evolution (LTE) physical downlinkcontrol channel (PDCCH) or enhanced physical downlink control channel(EPDCCH).
 13. The network node of claim 11, wherein the processor isoperable to transmit the first uplink/downlink scheduling pattern in aLTE physical control format indicator channel (PCFICH).
 14. The networknode of claim 11, wherein the network node serves a first cell and thefirst uplink/downlink scheduling pattern applies to a second celldifferent from the first cell.
 15. A wireless device comprising aprocessor and a memory, the processor operable to: receive, from anetwork node, a first uplink/downlink scheduling pattern for a firstplurality of consecutive subframes; receive or transmit at least onesubframe according to the first uplink/downlink scheduling pattern;receive, from the network node, a second uplink/downlink schedulingpattern for a second plurality of consecutive subframes, wherein thefirst plurality of consecutive subframes and the second plurality ofconsecutive subframes overlap in time by at least one shared subframe;and transmit or receive the at least one shared subframe; wherein thefirst uplink/downlink scheduling pattern comprises at least one of: aset of subframes in the first plurality of subframes that the wirelessdevice does not monitor for downlink; and a set of subframes in thefirst plurality of subframes that the wireless device does monitor fordownlink.
 16. The wireless device of claim 15, wherein the firstuplink/downlink scheduling pattern comprises: a first value representinga number of downlink subframes in the first plurality of consecutivesubframes; and a second value representing a number of uplink subframesin the first plurality of consecutive subframes.
 17. The wireless deviceof claim 15, wherein the processor is operable to receive the firstuplink/downlink scheduling pattern in a long term evolution (LTE)physical downlink control channel (PDCCH) or enhanced physical downlinkcontrol channel (EPDCCH).
 18. The wireless device of claim 15, whereinthe processor is operable to receive the first uplink/downlinkscheduling pattern in a LTE physical control format indicator channel(PCFICH).
 19. The wireless device of claim 15, wherein the network nodeserves a first cell and the first uplink/downlink scheduling patternapplies to a second cell different from the first cell.
 20. The wirelessdevice of claim 15, wherein the first uplink/downlink scheduling patterncomprises: a first value representing a number of downlink subframes inthe first plurality of consecutive subframes; and a second valuerepresenting a number of uplink subframes in the first plurality ofconsecutive subframes.